Tju_Oj_3517The longest athletic track

bool DSF(Node oneTreePoint ){   //传入的结点和其他有效信息
    visited[nowPoint] = 1; //当前点已遍历标记
    相关操作（随题更改）for( AllLinkNode){//遍历与此点相连的所有节点；
        if ( !visited[oneLinkNode] ){  //如果没有被访问过才能继续搜索；
            visited[onelinkedNode] = 1;    //标记已访问；
       　　　相关操作（随题更改）
            DSF( Node oneTreePoint);
        }
    }
    if(触底判断条件){
　　　　　执行操作；
        return true;
    }
    return true;
}

//建立一个vector数组，每个Vector中存放结构体数据类型；

struct LinkNode{
    int linkedPoint;
    int length;
};
vector <LinkNode> Tree[MAX];

//对vector数组清空
 for(int i = 0;i < MAX;i++)
    Tree[i].clear();

//插入
Tree[i].push_back( LinkNode n );
            

/*
 * 3517_The longest athletic track.cpp
 *    给定一个边长带有权值的树，求树的直径。
 *  Created on: 2018年11月8日
 *      Author: Jeason
 */
#include <iostream>
#include <fstream>
#include <string>
#include <cstring>
#include <vector>
using namespace std;
#define MAX 2001

struct LinkNode{
    int linkedPoint;
    int length;
};

int findMaxLength[MAX];
int findMaxPoint[MAX];
int numofMax;
int visited[MAX];
int start = 0;
vector <LinkNode> Tree[MAX];

bool DSF(vector <LinkNode> oneTreePoint ,int totalLength ,int nowPoint ){
    visited[nowPoint] = 1;
    int tmp = totalLength;
    for(int i = 0; i < oneTreePoint.size(); i++){//遍历与此点相连的所有节点；
        if ( !visited[oneTreePoint[i].linkedPoint] ){  //如果没有被访问过才能继续搜索；
            visited[oneTreePoint[i].linkedPoint] = 1;    //标记已访问；

            totalLength = tmp + oneTreePoint[i].length;   //如果为符合条件点，更新当前总长；
//            cout << "当前点" << nowPoint << " 和 " << oneTreePoint[i].linkedPoint << "长度为"  << totalLength << endl;
            DSF( Tree[ oneTreePoint[i].linkedPoint ], totalLength, oneTreePoint[i].linkedPoint);
        }
    }

    if(oneTreePoint.size() == 1){
        //说明找到了边缘的子叶，执行操作；
        findMaxLength[start] = totalLength;  //记录当前总长度；
        findMaxPoint[start] = nowPoint;  //总长度对应的点；
        start++;
//        cout << "get bottom:"<< findMaxLength[start-1] <<endl;
        return true;
    }

//    cout << "finsh at:"<< nowPoint << endl;

    return true;
}


int find(int findMax[MAX])
{
    int m = 0;
    for( int i = 0; i <= MAX; i++ )
        if( findMax[i] > findMax[m])
            m = i;
    return m;
}

int main()
{
    int T,point_num;
    int a,b,ab_length;
    cin >> T;
    while(T--){
        //初始化操作
        start = 0;
        numofMax = 0;
        memset(findMaxLength,0,sizeof(findMaxLength));
        memset(findMaxPoint,0,sizeof(findMaxPoint));
        memset(visited,0,sizeof(visited));
        for(int i = 0;i < MAX;i++)
            Tree[i].clear();

        cin >> point_num;
        point_num--;
        while(point_num--){//将数据存储在树结构中
            cin >> a >> b >> ab_length;
            LinkNode point1;
            point1.linkedPoint = b;
            point1.length = ab_length;
            Tree[a].push_back( point1 );
            LinkNode point2;
            point2.linkedPoint = a;
            point2.length = ab_length;
            Tree[b].push_back( point2 );
        }
        DSF(Tree[2], 0 , 2 );  //从编号为1的结点开始DSF；
        numofMax = find(findMaxLength);
//        cout << "第1次结束" << "，,离2最远的点："<< findMaxPoint[numofMax] << ";其长度："<< findMaxLength[numofMax] <<endl;

        int tempPoint = findMaxPoint[numofMax];
        memset(findMaxLength,0,sizeof(findMaxLength));
        memset(findMaxPoint,0,sizeof(findMaxPoint));
        memset(visited,0,sizeof(visited));

        DSF(Tree[tempPoint], 0, tempPoint );
        numofMax = find(findMaxLength);
//        cout << "第2次结束,离" << findMaxPoint[numofMax] << "最远的点："<< findMaxPoint[numofMax] << ";其长度："<< findMaxLength[numofMax] <<endl;
        cout << findMaxLength[numofMax] << endl;
    }

}